A balloon catheter (medical elongated body) is known as a medical instrument, which is used in a technique for widening a lesion area (stenosed site) formed in a biological lumen such as a blood vessel. The balloon catheter has a shaft and a balloon (dilation member) that is fixed to the shaft on a distal side.
The balloon fixed to the shaft on the distal side can be introduced into a biological lumen through a puncture site via an introducer sheath, a guiding catheter, or the like and is delivered to a lesion area. The balloon delivered to the lesion area dilates in a state of being disposed in the lesion area and applies a dilation pressure to the lesion area.
Recently, as a type of balloon catheter, a balloon catheter, in which a blade-like element formed of a resin having relatively high rigidity, a metal, or the like is attached to a balloon on an outer surface side, has been proposed (for example, refer to JP-A-2009-112361). In the balloon catheter, the balloon disposed in a lesion area dilates so that the lesion area can be widened while the element attached to the balloon on the outer surface side makes a nick in the lesion area. Therefore, the balloon catheter exhibits a particularly high therapeutic effect on widening a highly-calcified lesion (hardened lesion area due to calcification).
However, in the balloon catheter described above, since an element is attached to a balloon on an outer surface side, although the element can make a nick in a lesion area, it can be difficult to cause a dilation pressure of the balloon to evenly act on the lesion area in which the nick is made.
In order to preferably widen a lesion area in which a nick is made, a practitioner needs to perform a technique as follows. That is, a practitioner needs to make a nick in a stenosed site to a certain extent using the balloon catheter to which the element is attached. Thereafter, the practitioner needs to replace the balloon catheter with a balloon catheter to which no element is attached and to widen the stenosed site in which the nick is made. In the technique, a practitioner needs to separately use the balloon catheter to which the element is attached and a balloon catheter to which no element is attached, so that the technique becomes troublesome and economic efficiency in medical treatment deteriorates.